The use of special motion sensors is known for both the control of room lighting and in the outdoor area of buildings in addition to using switches and dimmers. Besides the advantageous automatic operation of the lighting means, motion sensors enable expanded possibilities to save on energy used for lighting. However, it is a disadvantage that additional effort is required on the device end for the motion sensors monitoring the area to be illuminated.
DE 20 2010 011 569 U1 reveals a device designed for brightness-dependent lighting. The device shown comprises means to detect a brightness level in an area illuminated by one or several light sources as well as means to regulate the brightness of at least one of the light sources. The regulation of the brightness thereby takes place at least partly based on the brightness detected in the illuminated area and a brightness value. The device shown thus enables a dynamic regulation of the lighting depending on the ambient lighting. The means for detecting the brightness is thereby disposed in the illuminated area, or in the area illuminated at least indirectly through reflection.
DE 10 2009 056 806 A1 shows an illuminated advertising that displays a printed circuit board supporting at least one lighting means. A brightness sensor is arranged on the printed circuit board which measures the ambient brightness. A control device controls a power supply of the at least one lighting means, so that a luminous intensity emitted by the lighting means increases with an increasing ambient brightness. The illuminated advertising is thereby operated with a brightness adapted to the ambient brightness.
The prior art, however, shows the measurement of brightness and the operation of a lighting means depending on a measured brightness, an evaluation of the measured brightness with regard to information contained in brightness measurements is however omitted. The detection of a reflected light in terms of its brightness is however definitely mentioned, but an evaluation of this brightness is not done.
It is a task of the present invention to detect a change of a reflecting object in a room with as little effort as possible.